Cellular attachment and the establishing of cell-cell contacts is one of the key questions in the development of advanced biomaterials. Many parameters that influence cell attachment, motility, and retention under external forces have already been established. Among these are the chemical properties and the presentation of specific functionalities and factors, but also geometric aspects of the distribution of cellular attachment sites (focal contacts) and the cellular geometry, both of which induce cellular responses and changes in phenotype. A systematic investigation of the influence of the nanoscopic distribution and size of focal contacts and of the microscopic cell shape on the stability of cellular adhesion will use a versatile, topography-free nanopatterned substrate produced by self-assembly. Using vascular endothelial cells as a naturally two-dimensional cell type of great clinical significance for the seeding of vascular grafts, this nanopatterning approach will shed light on how endothelial cells attach to surfaces, establish the required phenotype, and build a complete vessel lining by forming well-defined and stable cell-cell contacts. The hypothesis driving this work is that a nanopatterned distribution of well-defined attachment sites for the anchoring of endothelial cells results in a stable endothelium under physiologic shear stress. This hypothesis will be tested by (1) designing and fabricating smooth nanopatterned surfaces of controlled size and biological functionality using self-assembly methods, (2) seeding endothelial cells onto nanopatterns and analyzing their adhesion, cytoskeletal arrangement, and intercellular contact development and dynamics under both static and flow conditions, (3) contrasting the results of (2) with observations and measurements on topographic nanopatterned surfaces created by micromachining or molding processes. This study will reveal systematic relationships between endothelial cell differentiation and activity and the geometric and chemical properties of the underlying surface. The results will provide new design principles to enhance the seeding processes for either traditional polymeric or modern tissue-engineered graft materials to establish an endothelial cell lining that is capable of long-term prevention of vascular occlusion. Such principles could lead to the long-sought designed arteries that are tissue-engineered in their main structural components as well as in the inner lining, and shed light in general on the mechanisms of cell-biomaterial interactions.